A Massachusetts immigrant and refugee service group wants residents to be aware of human trafficking, which it says is more common than generally thought. Lutheran Social Services has scheduled an educational event tomorrow outside Worcester City Hall at which advocates will distribute literature and be available to help victims of trafficking find legal assistance. Jozefina Lantz, director of immigrant services at Lutheran Social Services in Worcester, said her group helps some victims who were brought into the United States as sex slaves. The event is part of National Human Trafficking Awareness Day. Analysts believe between 14,000 to 17,000 people are smuggled for profit into the United States every year.